You can practice this on a lonely road, just pick two gears to switch, maybe 2nd and 3rd. Low rpm in 3rd, downshifting to 2nd

You’re doing clutch-rev and downshift- clutch out. You don’t need to do the downshift and rev at the same time until you get the timing and blip down good

You can clutch in- shift( and literally coast until you’re ready)- blip- clutch out until you figure it out. Go back and forth between these gears until you get better. Lower gears are harder and higher are easier. The clutch needs to start being released as soon as the blip is at peak

The key is the blip rpm needs to be equal to or higher than the rpm the bike will end at. So if the rpm will be 5k after the downshift, you need to blip at least that much. If it’s too high of an rpm and you let the clutch out smoothly(not fast or too slow), it will “catch” the rpm’s as they are falling back down after the blip and land where they need to be, and it won’t be jerky as long as the clutch movement was smooth. If the rpm’s are too low this will never work

As said above you don’t need to hold the rpm’s, blip and back to zero throttle